Static mixer and method for mixing a main component with an additive

摘要

The invention relates to a static mixer (1) having a cylindrical mixer channel formed by a mixer channel housing (5) and a multistage mixer-wing element (3) which is arranged in said mixer channel and used for mixing layers of a hardening accelerator paste into a flow of highly viscous PU. Discharge openings (7) are provided in the inlet area of the static mixer. Said discharge openings introduce a partial flow of hitherto unmixed highly viscous PU into secondary channels (6) arranged parallel to the mixer channel. The secondary channels are connected to feeder openings (8) arranged in the wall of the mixer channel downstream from the mixer wing element (3) when seen in the direction of flow. The unmixed PU is guided in the secondary channels (6) and enters the outer area of the flow emanating from the mixer wing element via the feeder openings where the mixed layers of hardening accelerator paste are contained. The mixed flow is covered with a layer of unmixed PU to prevent layers of hardening accelerator paste from being discharged from an adhesive element applied with the aid of the mixer (1) and to prevent the occurrence of adhesive defects resulting therefrom.